1. Field of the Invention
The invention relates to a film assemblage which includes means for providing a processing liquid spreading assembly of a self-developing type camera with a gap of a predetermined value.
2. Description of the Prior Art
In photographic apparatus of the self-developing type, an exposed photosensitive element is processed by distributing a processing liquid in a thin layer between the photosensitive element and another element. The processing liquid may be provided initially in a rupturable pod or container coupled to one of the elements and is distributed between the elements by moving them in superposition together with the rupturable container through a convergent passage between a pair of juxtaposed pressure-applying members, e.g., rollers.
For optimum results, measured for example in terms of image quality and uniformity, as well as reliability and repeatability, the layer of processing liquid distributed between the elements of the film unit should be of a predetermined thickness. When the processing liquid is distributed by moving the elements through a convergent passage between a pair of pressure-applying members that are free to move apart from one another and are resiliently biased toward one another, the thickness or depth of the layer of processing liquid is dependent upon a number of factors, including the pressure exerted by the pressure-applying members, the viscosity of the processing liquid, the speed of movement of the film unit through the gap between the pressure-applying members, and the spacing between the pressure-applying members as the film unit enters the gap.
U.S. Pat. No. 3,732,099 discloses a camera of the self-developing type wherein the pressure of the pressure-applying members of a processing liquid spreading assembly on a film unit is varied in inverse relation to the ambient temperature (and thus to the viscosity of the processing liquid) to provide for distribution of the processing liquid in a layer of predetermined thickness. U.S. Pat. No. 3,604,329 discloses a similar type camera wherein the thickness of the layer of processing liquid spread between the elements of the film unit is controlled by maintaining the compressive force exerted on the film unit by the pressure-applying members substantially constant and varying the speed of movement of the film unit between the members to compensate for changes in the viscosity of the processing liquid. Still another example of the prior art relating to means for controlling the thickness of the layer of processing liquid spread between elements of the film unit is found in U.S. Pat. No. 3,882,518 wherein the spacing or gap between the adjacent surfaces of a pair of superposed rollers is controlled by a pair of adjustable screws. Also, see U.S. Pat. No. 4,104,669 wherein is described a camera having a bimetallic element which exerts a pressure on a film cassette so as to control the thickness of the layer of processing liquid.
While all of the above-described apparatus perform their intended functions well, there is still a need for a novel, simple, and inexpensive means for providing a spread of processing liquid which has a predetermined thickness.